What is the maximum equivalent length of a boiler’s flue?

October 24th 2023

The maximum horizontal equivalent flue lengths (after the first elbow) is: 20m

The maximum vertical equivalent flue lengths is: 21m

Allow 1.3 meters of flue length for each 87° bend

1.0 meters of flue length for each 45° bend.

 

Maximum horizontal equivalent flue lengths (m) Maximum vertical equivalent flue lengths (m) 87° Elbow (m) 45° Elbow (m)
NCB-CE 20 21 1.3 1.0
NCB300 7 8 1.3 1.0
NCB500 7 8 1.3 1.0
NCB700 20 21 1.3 1.0
LCB700 20 21 1.3 1.0
NPE A/S 20 21 2.4 1.2

 

Note: The maximum horizontal equivalent flue length is measured after the first elbow.

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